Olgor the Finder [ Purveyor of Misplaced Items ]

If you haven't raided Tier 3 raid content, you will only see the visible armor items for sale. Once you have successfully completed a raid mission, it unlocks the contents for that specific raid zone to see/buy; e.g., all content is shown when having beaten Beasts' Domain, Resplendent Temple, and Rubak Oseka raids.